Underwater launched carrier

ABSTRACT

An assembly capable of being launched from a submarine to carry into seawater an element responsive to a property of the water to be measured, comprising a carrier member coupled to the element, a lifting body shaped to provide hydrodynamic lift, a tether for mechanically connecting the lifting body to the submarine, the lifting body and the tether being constructed and arranged so that the lifting body, when connected to a moving submarine, will move through the water at a distance above the submarine, a supply of electrically conductive cable connected to the element and stored at least in part by the lifting body for payout to accommodate movement of the submarine relative to the member, and releasable coupling means for holding the member and the lifting body together during their launch from the submarine and thereafter releasing the lifting body from the member.

BACKGROUND OF THE INVENTION

This invention relates to submarine launched devices for measuring aproperty of seawater, e.g., a submarine bathythermograph (SSXBT).

Surface and air launched bathythermograph systems (XBTs) have been inuse for some years. Relevant technology is known, and is described,e.g., in Campbell et al. U.S. Pat. No. 3,221,556; Cate U.S. Pat. No. Re.27,103; and Costello U.S. Pat. No. 3,561,267. In general, aprobe-carried thermister is connected in a bridge circuit throughspooled wire arranged to pay out as the XBT descends and the launchvehicle continues its normal movement. Henricks et al. U.S. Pat. No.3,408,867 discloses technology for manufacturing a suitable wire.

While much of the XBT technology is useful in SSXBT systems (and thedisclosures in above-identified patents are accordingly herebyincorporated by reference), the latter present special problems, since,e.g., the probe must be carried to the surface before initiation of themeasuring and recording cycle, and the wire must be kept free of thesubmarine propulsion mechanism and control surfaces. Efforts to designan SSXBT appear in Bixby U.S. Pat. No. 3,520,188; Francis U.S. Pat. No.Re. 27,335; Crist U.S. Pat. No. 3,524,347; and Stohrer U.S. Pat. No.3,605,492.

SUMMARY OF THE INVENTION

The invention provides an improved assembly capable of being launchedfrom the aft signal ejector of a submarine with only minor modificationof the ejector breech door. The system overcomes the problems ofinterference with the submarine propulsion mechanism and controlsurfaces, and is reliable, easily manufactured and used, and makespossible highly accurate measurements under a variety of conditions.

In general the invention features an assembly capable of being launchedfrom a submarine to carry into seawater an element responsive to aproperty of the water to be measured, comprising a carrier membercoupled to the element, a lifting body shaped to provide hydrodynamiclift, a tether for mechanically connecting the lifting body to thesubmarine, the lifting body and the tether being constructed andarranged so that the lifting body, when connected to a moving submarine,will move through the water at a distance above the submarine, a supplyof electrically conductive cable connected to the element and stored atleast in part by the lifting body for payout to accomodate movement ofthe submarine relative to the member, and releasable coupling means forholding the member and the lifting body together during their launchfrom the submarine and thereafter releasing the lifting body from themember. In preferred embodiments the carrier member has a buoyancychamber and is coupled to the element for ascent through the water, themember including pressure responsive means for initiating downwardreturn of the element when the member reaches a predetermined reducedpressure zone in the water during the ascent; the lifting body has abuoyancy chamber; the coupling means is held in operative position bycoils of the tether which unwind during launch to permit release of thelifting body upon extension of the tether; the coupling means and thelifting body are surrounded by a housing wall, the housing being ventedto permit water to surround the coupling means prior to release of thelifting body; both the lifting body and the carrier member includescuttle valve assemblies; the lifting body has a longitudinal axis, apair of external wings, and an exterior shape having a rounded nose anda circular cross-section (except for the wings) transverse to the axis;the lifting body comprises a float having a nose at one end and a spoolfor storing the cable at the other end, and a skirt surrounding thespool; the carrier member comprises an elongated housing having thebuoyancy chamber in its forward portion, a ballistically shaped probecarrying the element is mounted in the housing, and pressure responsivemeans are provided to hold the probe in the housing and seal thebuoyancy chamber therein during the ascent, and to release the probe andopen the chamber to flooding upon ascent to the reduced pressure zone;and a spool is mounted in the housing aft of the probe, a portion of thesupply of cable being stored on the spool to pay out to accomodatevertical movement of the housing during the ascent while cable pays outfrom the lifting body to accomodate horizontal movement thereof, thespool and the housing having opposed flanges with sealing meanstherebetween to constitute the pressure responsive means, the housingbeing vented aft of the flanges to maintain the seal at elevated waterpressure.

Other advantages and features of the invention will be apparent from thedescription and drawings herein of a preferred embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially diagrammatic, partially sectioned view of a systemembodying the invention, with the SSXBT shown in the submarine aftsignal ejector;

FIGS. 2 through 5 are diagrammatic views showing the system insuccessive stages of operation;

FIGS. 6a and 6b respectively show in sectional view overall fragments ofthe SSXBT;

FIG. 7 is another fragmentary sectional view of the SSXBT;

FIG. 8 is a full scale sectional view of the lifting body assembly; and

FIG. 9 is a full scale elevation of the lifting body of FIG. 8,partially broken away.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIGS. 6a and 6b SSXBT assembly 10 is shown as stored prior to use,and has an outer housing 11 consisting of a forward tube 12 and an afttube 14 each crimped to splice ring 16; O-ring 18 seals tube 12 to thering.

The nose of tube 12 has an axial vent 20 sealed by tapered scuttle valve22 mounted on one end of rod 24, the other end of which extends intosleeve 25 of hollow pusher 26 and is swaged at 28 to prevent itsseparation from the sleeve. Coil spring 30 surrounds rod 24 betweensleeve 25 and retaining ring 32 fixed to the rod. The free end of pusher26 is aligned in axial opening 34 of bulkhead 36 fixed inside tube 12,and seats on the nose of bathythermograph probe 38, with spring 30compressed to force valve 22 into vent 20. The diameter of vent 20 issmall enough so that water pressure at the intended maximum launch depthof the SSXBT will be insufficient to open vent 20 by overcoming spring30.

Probe 38 is the general design disclosed in Campbell et al. U.S. Pat.No. 3,221,556 and, as shown in FIG. 6a, includes a thermister 50 and asea electrode 51 connected to two conductor cable 52 wound on spool 54for payout through the aft end 56 of the probe housing.

Bulkhead 36 closely surrounds the nose of probe 38 to protect the probeagainst axial shock, and a second bulkhead 55 similarly protects againstradial shock. Bulkheads 57 and 59 provide additional strength. Tubes 12and 14 are metal, except for the nose of tube 12 which is plastic.

Probe end 56 is received in sleeve 60 at the forward end of intermediatespool 62 on which is wound additional two wire cable 64. Cable 52 passesthrough opening 66 in the floor 68 of spool 62 and is electricallyjoined to cable 64 in potted cavity 69 in spool 62. Ports 70 areprovided in the cylindrical wall 71 of sleeve 60, and O-ring 72surrounds wall 71 adjacent spool flange 74. This intermediate spool andsleeve assembly extends through splice ring 16, and is positioned withflange 74 just aft of and aligned with flange 76 of the splice ring;O-ring 72 provides an axial seal between the flanges and, with O-ring18, the potting in cavity 69, and valve 22, seals off the interior oftube 12. PVC spaghetti 78 protects the length of cable 52 between probeend 56 and cavity 69.

In the aft portion of splice ring 16 are a series of circumferentiallyspaced ports 80 aligned with similar ports 82 in tube 14, and the tubeis staked (e.g., at 84) to the ring fore and aft of the ports.

Axial push rod 88 has a head 90 seated in the end of spool 62, extendsthrough brass eyelet 92 in guide 94 near the forward end of taperedlifting body skirt 96, and has its end 98 seated in lifting body scuttlevalve assembly cap 100. Cable 64 from the intermediate spool 62 passesthrough eyelet 92 and is wound around lifting body spool 102.

The lifting body assembly includes a float 110 with a vent 111 in itsnose, and having as its aft portion spool 102, skirt 96 which has itssmall diameter end secured by adhesive to the float just forward ofspool 102 and extends beyond the aft end of the spool, and a scuttlevalve assembly 112. The valve assembly includes cap 100 seated in theopen end of spool 102 and sealed thereto by O-ring 114, rod 116 held incap recess 118 by pin 120 in elongated (to permit axial movement of therod in the passage) slots 122, needle valve 124 at the other end of therod, and coil spring 126 compressed between cap 100 and retaining ring128 on the rod to hold valve 124 in vent 111.

Float 110 is made in two pieces held together and reinforced by splicering 130, with bonding adhesive in cavity 132.

Tether 140 (fifty feet long) consists of a nylon tow cord 142 attachedto float 110 at 144, and two conductor insulated steel cable 146electrically connected to wire 64 in potted cavity 148. The tether iscoiled around the float, with its last few turns held in place by rubberband 150 through openings 152 and 154 of which the tether passes. Thefree end of the tether is tied to tube 14 with string 156.

Parallel attitude control wings 160, 162 on opposite sides of skirt 96form an angle of 10° with the horizontal (as seen in FIG. 8). FIGS. 8and 9 are drawn to full scale for the particular embodiment disclosed,and show the preferred dimensions and orientation of the wings, and thepreferred location of the tether connection to the lifting body.

Wireform 170 is shaped to form two straight-legged elongated loops 172,174; one leg of each loop is integral with semi-circular connector 176,and the other leg of each loop extends past connector 176 to terminatein a hook 178, 180. A tab 182, 184 is interlocked in each loop. The tabsfit in recesses 186, 188 at opposite sides of skirt 96, between wings160, 162. The recesses have sloping floors and decrease in depth in theaft direction. Several turns of tether 140 are wound over tabs 182, 184and loops 172, 174 to retain them in place against the skirt. The freelegs of the loops extend through notches in splice ring 16, and springs190, 192 connect hooks 178, 180 to a more forward portion of the splicering, thereby drawing the lifting body assembly against the intermediatespool assembly.

Shipping plug 200 is held in place in the open aft end of tube 14 byclips 202, which are in turn secured by tape 204. Coil spring 206 iscompressed between plug 200 and cup 208 (which protects the float walland finish from damage by the spring), and holds the lifting bodytightly against the intermediate spool during shipment and storage.

The free end of the tether cable 140 has an enlarged connector 210 withaxially offset cutouts 212 and 214 on opposite sides, each cutoutexposing a segment of one of the wire conductors in the cable. Awaterproof, flexible boot 216 fits over connector 210 and is sealed tothe cable at 218.

The SSXBT is designed for launching through the aft signal ejector of asubmarine, after slight modification of the breech door. FIG. 1 showsthe SSXBT inserted in the ejector 220, past spring biased detent 221after removal of the shipping plug, spring 206 and cup 208. Tether 140is threaded through a gland 222 provided in breech door 224, which glandcan then be tightened around the tether to provide a seal. A wire grip226 is attached to the tether outside the gland to isolate cable tensionfrom connector box 228 to which conductor 146 is connected. Shear 227 isprovided to sever the tether after completion of a use cycle. Box 228has a lever operated switch 230 to complete the electrical connection,and a cable 232 leading to recorder 234. The recorder includes chartpaper 235 which is advanced during operation to provide recordation ofthe temperature vs. depth relationship sensed by the SSXBT probe.

FIG. 1 shows the arrangement of connector 210 in box 228. Two sets 240a,b, c, and 242a, b, c, of opposing, spring-biased, retractable contactsare provided, respectively at opposite sides of channel 244 designed toreceive connector 210 after removal of boot 216. Contacts 240a and 242aare connected in parallel, and one of them will fit into cutout 212 whenthe connector is inserted against stop 250. Similarly, either contacts240b and c or 242b and c will fit in cutout 214. The provision ofaxially (of the cable connector) offset contacts and cutouts ensuresconnection with the proper polarity no matter how the connector isinserted.

To use the SSXBT after its placement in the signal ejector as describedabove, with the breech door closed and locked, and with the tether cableinserted into the connector box, lever 230 on the connector box is movedto complete the electrical circuit between the SSXBT and recorder 234,initiating a checking cycle during which a calibration temperature isrecorded on chart paper 235. At the end of the checking cycle the systementers its launch mode, during which ejector tube 220 is flooded and theSSXBT is launched from the submarine through conventional operation ofthe signal ejector.

As the SSXBT rises from the submarine, the tether uncoils from liftingbody float 110, breaking string 156 and pulling rubber band 150 off inthe process, and quickly becomes fully extended.

As housing 11 continues upward (FIG. 2), by virtue of the buoyancy dueto the air trapped in tube 12, the tether draws the lifting body out oftube 14, with tabs 182, 184 (which were released as the tether unwound)sliding back and out of skirt recesses 186, 188. Ports 80 and 82 ensurethat the zone between intermediate spool flange 74 and the lifting bodyis at ambient water pressure, so that the intermediate spool is notdrawn out of tube 12 as the lifting body separates, and similarlydecoupling the lifting body from housing 11. With the aid of thehydrodynamic lift due to the shape of float 110 and skirt 96, and thebuoyancy due to the air trapped in the float, the lifting body movesthrough the water above the submarine inclined at about 10°-30° to thehorizontal, holding the tether free of the propeller screw and the aftcontrol surfaces of the submarine, as shown in FIG. 3. Wings 160, 162help to maintain the angle of inclination in the desired range. Waterpressure at the submarine depth (e.g., 50-1000 feet) keeps valve cap 100seated and sealed in spool 102, but is insufficient to unseal valve 124from vent 111. During this ascent phase, wire 64 pays out from spool 62in response to vertical movement of housing 11 relative to the liftingbody, and wire 64 pays out from spool 102 in response to horizontalmovement of the submarine-drawn lifting body through the water, so thatthe wire once payed out is not drawn through the water, minimizing theforces applied to the wire and permitting use of a very fine gauge.

Water pressure is sufficient to maintain the seal at O-ring 72 untilhousing 11 reaches the surface, at which point the intermediate spooland probe drop out of tube 12, as shown in FIG. 4. When the probeelectrode 51 contacts the water the electrical circuitry in the SSXBTsystem is triggered to initiate a measurement and recording cycle duringwhich the temperature profile sensed by the thermister as the probedescends to the bottom is recorded on the chart. The intermediate spoolslowly follows the probe to the bottom (FIG. 5). As probe 38 falls, wire52 unspools at a rate equal to the probe's speed of descent, therebyreducing wire tension.

When probe 38 drops out of housing 11 the spring force on scuttle valverod 24 is released, opening vent 20 to permit escape of air as tube 12fills with water. The flooded housing then drops to the bottom (FIG. 5).

Upon completion of the measurement and recording cycle, shear 227 isoperated to sever the tether wire, and the buoyancy in float 110 causesthe lifting body to rise toward the water surface. At about 15 feet fromthe surface the reduced water pressure is insufficient to maintain theseal at O-ring 114, valve 124 is released, and air escapes through vent111 as float 110 fills with water through its aft end. Cap 100 issufficiently heavy to keep the nose of the float up (so that air is nottrapped in the partially flooded float) until the float is fully floodedand drops to the bottom.

An overall diagram of the electromechanical system appears in FIG. 1.Bridge circuit 260 includes the probe thermister and is preferably alongthe lines described in said U.S. Pat. No. Re. 27,103. Other details ofthe circuitry in recorder 234 and connector box 228 may be as desired,and form no part of the present invention. The trigger delay circuit 262prevents premature initiation of the measuring and recording cycle. Asin the conventional surface launched XBT system, one version of which isdescribed in said U.S. Pat. No. 3,221,556 (the currently used version isavailable from The Sippican Corporation, Marion, Mass.), the circuitryis designed to initiate the measuring and recording cycle in response toa signal produced by contact of the probe with the water. When the SSXBTis flooded in the submarine signal ejector tube there is immediatecontact of the wire on spools 62 and 102 with the water, producingtransient currents due to capacitative discharge which would trigger themeasuring and recording cycle if not suppressed. Then, when the probe isfirst exposed to the water as housing 11 reaches the surface, 1.4seconds is required for the probe to actually discharge from the housingand turn over to begin its descent. The trigger delay circuit includes arelay 264 which during launch disconnects the recorder from the rest ofthe system, and a second bridge circuit 266 employing seawater return asa leg. This bridge feeds a comparator 268 which in turn drives an RCdelay circuit 270. When the comparator 268 detects a seawater returnpath, the RC circuit charges. After 1.4 seconds of charging, a secondcomparator 271 with built-in hysteresis turns off the disconnect relay,instantly connecting the recorder bridge circuitry to the probe andtriggering the measuring and recording cycle.

Other embodiments are within the following claims.

I claim:
 1. An assembly capable of being launched from a submarine tocarry into seawater an element responsive to a property of the water tobe measured by a measurement circuit, comprisinga carrier member coupledto said element, a lifting body shaped to provide hydrodynamic lift, atether, said tether being connected at one end to said lifting body, sothat when the free end of said tether is connected to a moving submarinesaid lifting body will move through the water at a distance above saidsubmarine, a supply of electrically conductive cable connected to saidelement for electrically connecting said element in said measurementcircuit, said lifting body including means for storing at least part ofsaid cable for payout to accommodate movement of said submarine relativeto said member, and releasable coupling means for holding said memberand said lifting body together during their launch from the submarineand thereafter releasing said lifting body from said member.
 2. Theassembly of claim 1 wherein said carrier member has a buoyancy chamberand is coupled to said element for ascent through the water, said memberincluding pressure responsive means for initiating downward return ofsaid element when said member reaches a predetermined reduced pressurezone in said water during said ascent.
 3. The assembly of claim 2wherein said carrier member comprises an elongated housing having saidbuoyancy chamber in its forward portion, a ballistically shaped probecarrying said element is mounted in said housing, and pressureresponsive means are provided to hold said probe in said housing andseal said buoyancy chamber therein during said ascent, and to releasesaid probe and open said chamber to flooding upon ascent to said reducedpressure zone.
 4. The assembly of claim 3 wherein said housing has anose with an air vent for said chamber therein, and there is provided ascuttle valve assembly for sealing said vent.
 5. The assembly of claim 3further comprising a spool mounted in said housing aft of said probe, aportion of said supply of cable being stored on said spool to pay out toaccomodate vertical movement of said housing during said ascent whilecable pays out from said lifting body to accomodate horizontal movementthereof, said spool and said housing having opposed flanges with sealingmeans therebetween to constitute said pressure responsive means, saidhousing being vented aft of said flanges to maintain said seal atelevated water pressure.
 6. The assembly of claim 1 wherein said liftingbody has a buoyancy chamber.
 7. The assembly of claim 6 furthercomprising a scuttle valve assembly mounted in said lifting body to sealsaid buoyancy chamber at elevated water pressure, including a valveresponsive to reduced water pressure at the water surface to unseal saidchamber for flooding and scuttling said lifting body after severing ofsaid tether.
 8. The assembly of claim 1 wherein said releasable couplingmeans is held in operative position by coils of said tether which unwindduring said launch to permit release of said lifting body upon extensionof said tether.
 9. The assembly of claim 1 wherein said lifting body hasa longitudinal axis, a pair of external wings, and an, exterior shapehaving a, rounded nose and a circular cross-section except for saidwings transverse to said axis.
 10. The assembly of claim 1 wherein saidlifting body comprises a float having a nose at one end and a spool forstoring said cable at the other end, and a skirt surrounding said spool.11. The assembly of claim 1 further comprising a housing wallsurrounding said coupling means and said lifting body.
 12. The assemblyof claim 11 wherein said housing is vented to permit water to surroundsaid coupling means prior to release of said lifting body.
 13. Theassembly of claim 1 comprising a SSXBT wherein said element is athermister.